


Vulnerable

by DuncanByrne



Category: Star Trek, Star Trek: Alternate Original Series (Movies), Star Trek: The Original Series
Genre: BDSM, Emotions, M/M, Porn with Feelings, Relationship Growth, Tension
Language: English
Status: Completed
Published: 2018-06-10
Updated: 2018-07-04
Packaged: 2019-05-20 10:14:32
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 2,922
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14892701
Author URL: https://archiveofourown.org/users/DuncanByrne/pseuds/DuncanByrne
Summary: Spock reveals an embarrassing secret to James, and their relationship adjusts





	1. Chapter 1

“Come on, just get it out.”

Spock rested his hand on the goosebumps of his bare shoulder as his eyes shifted from Jim’s down to his lap. 

“Come on. You act like I’m going to chew you out.” Jim lifted Spock’s chin until his gaze met the Vulcan’s. “Just tell me, you can be honest. Don’t be worried. Why do you think I’m going to be mad?”

“That is not my concern. I do not predict that you will react with anger. Yet...”

“What?” 

Spock paused and again looked away from Jim.

“There is a distinct possibility you will react to my confession with disgust, or, at the very least, mild or moderate disapproval.”

“No, no! Don’t worry about that. Listen,” began Jim, directing Spock’s gaze towards his and smiling. “You don’t need to be ashamed.”

Spock sighed and squeezed the hand at his jaw. 

“Have you ever familiarized yourself with the psychology of paraphilias?”

“Fetishes? Yeah, some of them I know about.”

“In essence,” began Spock, “I am a biastophile.”

Jim looked at Spock curiously, trying to rack his memory to see if he knew the word. 

“Uh, what?”

Another sigh. 

“Biastophilia. It is the condition of sexual arousal being dependent upon the element of a non-consensual fantasy being present during erotic activities.” He shuddered. “To speak candidly, during our sexual intercourse, it would lend me great arousal if we simulated a rape scene. When we are not together, I often find myself fantasizing about you taking advantage of me.”

Jim frowned. 

“You mean you want me to pretend to rape you?”

Spock nodded slowly. 

“Once our shift is out, run into our quarters, demand you strip in front of me, tie your wrists and ankles to this bed, and fuck the hell out of you while you yell at me to stop? You would enjoy that?”

Spock nodded again, a grimace on his face as he rose from his seat at the edge of their bed.

“Captain, it was for this purpose that I was well aware I should never have told you--” 

“Stop!” 

Jim rose, rushed to Spock before he could open the door to the bathroom, and grabbed him forearm, nails dug into his skin. 

“Captain--”

“You better watch out.”

Spock frowned. 

“What is your meaning?”

“You better watch out when we try this out tomorrow.”

Jim winked as an astonished Spock felt an unwilling smile break out.


	2. Chapter 2

“Is it ok if I start now?”

“Yes,” Spock said. “I trust you to remember the guidelines we discussed earlier.”

“Yes yes yes, I get it.” Kirk gave his winning smile and put his hands on his hips as he looked down at the green flush on Spock’s cheeks. “I’ll rough you up and keep the heat on unless you say ‘Harcourt.’ Don’t worry, you know me. I’ll do just fine.” 

“I eagerly await your performance, Jim.”

“Don’t call me Jim!” He crossed his arms on his chest. “You will address me as Captain!”

“I see no reason to address you officially in an informal setting such as the bedroom, and additionally find--”

“And I see no reason for you to be wearing those annoying Starfleet uniform pants!”

“Please, please, cease---” Spock winced as Kirk lunged forward, hands grabbing below his waist, snatching the zipper down, nails digging into the skin of his thighs. “Cease--” he asked again, trying to stifle a smile towards the leering smile inches from his face. “Please! Cease, Captain.”

Kirk mashed his face against Spock’s as he shoved his tongue down the Vulcan’s throat, his hand creeping down towards Spock’s groin, until his limbs became rigid, hands frozen at Spock’s thighs, and gulped. Spock squinted and stopped kicking against Kirk. 

“Do you remain comfortable with these activities?”

Kirk shook himself and frowned. 

“Yes, of course!” His hands moved upwards to grab Spock’s chin and roughly move it to be in his line of vision.”Enjoyable for me, but not for you, I’m guessing!” 

Spock felt cold air on the sensitive tip of his penis as its upright structure was jerked out of his pants, the scratch of used bedsheets scrape against his pubic hair as cold fingers turned his body over and pried open his ass. Spock groaned, trying to clutch his muscles together and flail as much as he could while a sweaty Kirk whipped out his cock and advanced towards him. 

“Cease! Please, Captain, Cease!” 

“You’re not getting away from your master until I come on your back, Mister!”

Spock gave an especially hard kick to the arms framing him on the sweaty bed, flinching when Jim’s backhand slammed down on his back with a loud smack, sucking in his breath when Jim’s cock began to poke at the opening of his anus. Spock braced himself, his eyes squeezed shut, adrenaline pumping through his tight muscles as he awaited the grueling, terrible, terrific feeling of finally being taken advantage of by his own captain--

It wasn’t there. Kirk was still: panting in loud, heavy breaths, faltering over Spock’s trapped form. A droplet of water dripped onto Spock’s back. He turned around to face Jim. 

“Jim!”

“Spock--I’m so sorry.”

“Jim!”

Spock rose to his feet and gently laid his arms on Kirk’s shoulder as he saw the kneeling man’s face contorted into a pained sob, tears streaming down his bloodshot eyes. 

“Speak to me. It is imperative that you speak to me. What is wrong?”

Jim shook his head and looked Spock in the eye. 

“I thought I could do it. I’m sorry. I’m so sorry. I think I’m not ready quite yet.” His eyes left Spock’s and fell to the floor, nearly closing. “I’m so sorry for leading you on like that, but I can’t finish right now.”

“No, you must not apologize for your emotional state. Do not apologize.”

“But I said I would play it out for you!”

Spock tilted Jim’s face up until their eyes locked. 

“Listen, Jim, and internalize my meaning closely: my sexual fetishism is not an activity centered around me. It is intended only for the enjoyment of both you and me. If you feel discomfort during a roleplay, then its purpose has been forgone. Do you understand?”

Jim hid his eyes with his palms, smudging messy tears against his eyelids. 

“I’m sorry,” he choked out. “I’m sorry, I was trying to be the big guy in your fantasy and finally please you for once, and I only--I couldn’t bring myself to hit you and hurt you like that. Didn’t that hurt?”

“Yes, being struck caused me pain.” Kirk’s eyes widened and welled up. “But you were performing very satisfactorily,” Spock assured hurriedly. “Do not be ashamed. Your application of physical pain was a entirely pleasant sensation.”

“I’m sorry, I think I need time to get used to this.” He blinked and stared Spock up and down, eyeing his dying erection dolefully. “I’m sorry I disappointed. I think I just wasn’t prepared.”

“You are only human, Jim.” Spock put his hand on Jim’s and squeezed. “Human emotions are frequently unpredictable and incomprehensible. You were only attempting to satisfy my fetish. You bear no culpability for the way you feel.”

“I promise I’ll try again soon, ok?”

“If it would be agreeable to you to attempt this roleplay on another occasion, then I will certainly participate.” 

Spock put his arm around Jim’s shoulder.

“However, if this occasion does not arise, it will not matter to me.” He paused. “Do not worry. I love you regardless of the situation you and I are in.”


	3. Chapter 3

“Which actions were psychological disturbances to you?”

Kirk fidgeted with his collar and took another sip of his coffee, glancing around the empty rec room nervously. 

“Honestly, I felt the most, well--how should I put it--squeamish, let’s say, about causing bodily harm to you. You know, smacking you, and then getting ready to really shove into you right after I hit you. I just haven’t ever done something that extreme.”

“It is easily comprehensible why further precautions should have occurred previous to the attempt.”

“I hate to ask it, but I have to--what is it about the hitting? The meanness, the dominance, the...well, the violation of it all? How do those things make you feel?”

“Captain, I must first remind you that my feelings are much more restrained than yours and should not factor into this discussion as strongly as yours. However, the sexual arousal received from those elements stems from the excitement and the desirable sensation of unabated passion presented by the illusion of rape. You were not preparing to rape me. You were merely on the brink of a much more arresting sexual fantasy enactment than most humans are accustomed to.”

“What? You’re saying Vulcans usually like it that rough?”

“I do not presume to be aware of the sexual habits of my entire species, but to be brief, yes. Many of my kind have an evolutionary basis for the appreciation of the simulation of ravishment. Vulcan history has not always been so sanitized.”

“Alright, sure, you like the feeling that I’m all strong and demanding and I can’t control myself. But you’re sure you want me to rough you up too?”

“Yes. I trust you with this so-called ‘roughing up.’ And I offer you the option to halt sexual activity at any point, as always.”

“I know. You always have that option too. Just tell me if you need to stop. With the safeword, of course. With this kind of shit I guess you’ll be telling me to stop and you’ll be playing along, huh?” Kirk laughed. 

Spock nodded earnestly. 

“That is certainly the intention.”

Kirk leaned forward and dipped his finger into Spock’s coffee. 

“What types of things are you interested in?”

Spock raised his eyebrows with a half-smile. 

“Perhaps you are capable of guessing the sexual acts which interest me.”

“Is that a challenge?”

“Indeed.” 

“All right...you just nod your head when I land on something you’re interested in.”

“Proceed.”

“Well then. How about rough anal sex?”

Spock nodded. 

“Rough oral sex? Where you choke?”

Spock nodded.

“Anal sex toys?”

Spock shook his head. 

“Oh, so not everything. Ok. What about facials?”

Nod.

“Some mean talk? I should yell at you and call you nasty names?”

Nod.

“Really?”

“Do you disapprove of that desire?”

“Oh no, no. Sorry.” Jim paused and then shrugged. “You know, I didn’t expect you to like that kind of thing, but whatever floats your boat.”

“In that case, perhaps you should continue your interrogation.”

“Ball-slapping?”

Nod. 

“Dildos?”

Head shake.

“Spanking?”

Nod. 

“With an object or my hand?”

“Your hand will do.”

“Ah, I see, Mr. Spock. You’re excited to have your husband play out your rape fantasy however he wants, as long as it’s him doing the fucking and not a toy.”

“Precisely. I will desire your continued proceedings in spite of my repeated requests for you to stop. It is vital that that component remain fresh in your memory--do not stop.”

“Oh, You’ll be asking your husband here to stop, very soon,” he smirked.


	4. Chapter 4

Kirk leaned against the bathroom counter, his pants at his ankles, and slathered a generous portion of contraband Romulan lubricant on his already firm cock. 

“Do you feel certain of your willingness to once again attempt this experience?”

Kirk smiled over at Spock’s fastidiousness while the Vulcan removed his uniform, folding the slacks, socks, tunic, and boxers and neatly placing them in the cabinet under the mirror. 

“Yes, darling.” He stared at Spock’s inquisitive stare, at the attentiveness in those eyes that he’d always loved. “Yeah, this time, I think I’m ok with it.”

Spock walked over to the bathroom and laid a hand on Kirk’s bulging bare bicep. 

“There is no need to attempt to impress me at the expense of your own pleasure.”

“Oh, I know. I know.”

“I desire certainty that this roleplay will this time become one which arouses both of us, instead of exclusively me.”

“Yes. I promise.” Kirk touched the hand on his chest gently and lay another on Spock’s cheek. “After talking about it again, I know what I’m going to do. I promise.” He raised the hand on his chest and pressed his lips to the smooth surface. “I’m excited this time. Trust me. I’ll keep in mind what we were talking about for boundaries.”

“Do you feel sufficiently prepared to initiate?”

Kirk slapped Spock’s hand from his mouth with a sly grin. 

“You bet your bottom dollar I’m ready. You think you can handle me?” He swaggered forward, pushing Spock backwards towards their bed. “I’ll fuck you so hard you’ll never cheat with Leonard again!”

“Captain, I have never cheated on you, not with Dr. McCoy, nor any other male with--”

“That’s a lie and you know it!” 

“Then why do I see you getting all friendly with him and having drinks together in your off-time?”

“We merely fraternize, and the---”

“Liar!”

An aggressive shove, and Spock fell limply onto his back, his belly pressed against the inflamed foreskin of his captain as Kirk towered over him, his face leering mere inches from his. “And you need to be punished for lying!”

“Captain, please spare me---”

“I am not sparing you ANYTHING!” screamed Kirk. “You’re just a lying, calculating, alien whore, trying to cheat me and tease me, and I won’t take it!” 

Kirk held out the back of his hand next to Spock’s flinching closed eyes, and paused. 

Looking down, he surveyed the gorged hardness of Spock’s cock, the green flush spread on his cheeks, the goosebumps coating his arms, the clenched grip of his nails into his arms. He took a deep breath and shook himself for a moment.

Kirk smiled and brought down his hand against Spock’s face--he gasped, mouth wide open, a white mark from Kirk’s silver ring on his cheekbone, his erection twitching in spite of his resistance.

“You enjoying it, you weak little green-blooded twink? Huh?”

Kirk struck Spock’s other cheek with his sweaty palm, hard enough this time to jerk Spock’s face to the right. 

“Well? You whore!” Another strike. “I bet you enjoy this type of pain. I can just see you waiting for me to fuck you!” Kirk screamed, hitting Spock’s cock tersely. 

“No!” Spock objected, his voice rising. “Cease. Cease! I am in physical pain! I am incapable of withholding--”

Kirk cut off his words as he clambered forward and straddled Spock’s neck, forcing his erection in and out of the Vulcan’s agape mouth in quick, jerky thrusts. Spock flailed under the weight of Kirk’s ass pressing down on his chest, his cock waving wildly in the air with every tortured squirm attempting to escape the insertion into his mouth. Kirk racked his memory for the details of yesterday’s conversation. He smirked as he gave a rough slap to Spock’s balls, realizing how much Spock must have been enjoying his beating from the resigned swirls of his tongue around the cock jammed in his mouth.

“Incapable of what? Sucking a good cock?” Kirk thrusted deeper into Spock’s throat. “Incapable of taking your captain up the ass?” Spock suddenly bit down lightly on Kirk’s head, making him sputter and whip himself out of Spock with an enraged scowl on his sweaty face. 

He knew his husband. He knew what Spock wanted from this.

“You never. NEVER. Do that to ME. You will be DISCIPLINED for that, you half-breed!”

Positioning Spock on his stomach, his face pressed into his pillow, Kirk clashed his hand against Spock’s cheeks as hard as he could, over and over and over against his raw flesh. Spock roared in pain, overpowering the sound of the smack against his tender ass in his throaty cry. 

This was the moment. 

As Spock reeled from the bruises starting to form on his ass, Kirk fisted his cock, spread Spock’s cheeks wide open, and positioned himself at the sweaty entrance to his victim’s pleasure. Kirk forced himself in, smearing lube on the walls of Spock’s anus as he jolted his way into him, moaning at the feeling of Spock’s nervous limbs clenching his tightness around his master’s cock, penetrating as deep as he dared without a care in the world for the pain his random strokes were inflicting upon Spock. 

Reaching around to the front of Spock’s squirming form, Kirk’s greedy fingers found his cock and began tugging vigorously, squeezing him and tugging him in unison with his shoves into his puckering asshole. 

Spock lapsed first--shuddering violently as soupy green cum spurted out of his manhood onto the sheets, wincing in pain as Kirk’s hand did not relent on him for several seconds after his cock was emptied. 

Kirk continued to smack against Spock’s asshole, faster and faster, until he rolled the Vulcan onto his back suddenly, positioned himself at Spock’s face, and drenched his forehead with dripping white ejaculate, coating the contours of his cheeks. Spock opened his mouth, attempting to drink up the cum that oozed from his forehead. Kirk laughed.

“That’s a good little boy.” He gave a condescending pat to Spock’s slimy face, smiling at his eager attempts to suck up every drop of his pleasure. “Do you apologize for being a bad boy now?” 

Spock looked up and nodded gently. 

“That’s good, very good.” Kirk looked around the room awkwardly, wondering what to do.

Spock sat up slowly, his gaze locked on Kirk’s, and leaned towards him. 

“Jim.”

“Yes?” Kirk asked quietly. 

“That was utterly, miraculously, fascinating.”

**Author's Note:**

> Thank you for reading! Please feel free to leave feedback


End file.
